A study of the spectral sensitivity of retinal ganglion cells in the cat has been made using strong chromatic adaptation and spatial localization of the stimulus to the receptive center and/or periphery. The results have shown that three independent and chromatically distinct cone receptor systems appear to coverage on many if not all ganglion cells. Most show simple additivity rather than opponency in the same region of the receptive field. A rare cell did show opponency however. Blue receptor input is found in a high percentage of ganglion cells, although not in opponency between center and periphery.